Leisure time physical activity, cardiorespiratory fitness, and plasma fibrinogen concentrations in nonsmoking middle-aged men

Purpose: The relationship of both leisure time physical activity and predicted maximum oxygen consumption (VO₂(max)) with plasma fibrinogen concentration was examined within a cohort of employed middle-aged men. Methods: Analyses were performed on a subsample of 635 nonsmoking men (46.7 ± 7.7 yr) who completed a preventive medical assessment between 1992 and 1996. Results: Among nonsmokers, mean age-adjusted fibrinogen concentration decreased significantly with higher physical activity index (PAI) categories and quartiles of predicted VO₂(max) (mL · kg^-1 · min^-1) (both P = 0.001). Mean age-adjusted plasma fibrinogen concentrations were significantly different (P < 0.05) between inactive and vigorous PAI groups and extreme quartiles of predicted VO₂(max) (mL · kg^-1 · min^-1). These relationships were no longer significant after adjustment for the confounding effect of other ischemic heart disease risk factors. Stepwise multiple regression analyses showed that age, sum of skinfolds, and blood leukocyte count were the strongest predictors of plasma fibrinogen concentration. Conclusion: These data do not confirm a significant independent association of both physical activity and predicted VO₂(max) (mL · kg^-1 · min^-1) with fibrinogen concentrations among nonsmoking middle-aged men of similar high social class.